Geothermal system for heating water

ABSTRACT

A system and method for heating water with heat obtained from liquid that is sourced by a ground-loop system, the system including a ground-loop heat exchanger, a compressor, a hot-water-reservoir-loop heat exchanger, a subcooler heat exchanger, and a thermostatic expansion valve. The ground-loop heat exchanger is structured to transfer heat from heated ground liquid to a refrigerant. The compressor is structured to increase a pressure of the refrigerant received from the ground-loop heat exchanger. The hot-water-reservoir-loop heat exchanger is structured to transfer heat from the refrigerant to water received from the hot-water reservoir. The subcooler heat exchanger is structured to transfer heat from the refrigerant to the ground liquid before returning the liquid to the ground-loop system, and the thermostatic expansion valve structured to control a flow of the refrigerant to the ground-loop heat exchanger.

BACKGROUND Technical Field

The present disclosure pertains to a system for heating water and more particularly to a closed-loop refrigerant system with a subcooler heat exchanger to heat water utilizing heat from a separate geothermally-heated system.

Description of the Related Art

Rising energy prices and the desire to utilize renewable energy sources has made geothermal energy an attractive option. In the past heat conventional heat pumps have been employed to extract heat from the ground for use in residential and commercial heating applications.

Most heat pumps employ a refrigerant to transfer heat from the ground to a target water supply. This heat transfer generally results in a phase transition of the refrigerant from a liquid to a gas. But the temperature of the refrigerant is generally still below the desired temperature of the target water supply. The temperature of the refrigerant can be increased by increasing the pressure of the gaseous refrigerant. The heated high pressure gaseous refrigerant is then used to heat the target water supply, which results in another phase transition from a high pressure gas to a high pressure liquid. The refrigerant is then cooled by reducing the pressure of the liquid refrigerant. The temperature and pressure at which these phase transitions occur can be dependent on the type of liquid used as the refrigerant.

Unfortunately, the limitations imposed by the phase transition properties of the refrigerant impose a limit on the maximum heating temperature of the target water supply. Moreover, it can increase the external energy needed to cause the phase transitions of the refrigerant. In some instances, it can require additional external heaters to further heat the target water supply.

BRIEF SUMMARY

In accordance with one aspect of the present disclosure a system and method is provided for heating water that is used to heat water in a hot-water reservoir with heat obtained from liquid that is sourced by a ground-loop system. The system includes a ground-loop heat exchanger, a compressor, a hot-water-reservoir-loop heat exchanger, a subcooler heat exchanger, and a thermostatic expansion valve. The ground-loop heat exchanger is configured to receive ground liquid from the ground-loop system that geothermally heats the ground liquid and to transfer heat from the ground liquid to a refrigerant. The compressor is coupled to the ground-loop heat exchanger and configured to increase a pressure of the refrigerant received from the ground-loop heat exchanger. In some implementations a suction line accumulator is used to provide a constant volume of refrigerant to the compressor. The hot-water-reservoir-loop heat exchanger is coupled to the compressor and to the hot-water reservoir and is configured to receive the refrigerant and transfer heat from the refrigerant to water received from the hot-water reservoir. The subcooler heat exchanger is coupled to the hot-water-reservoir-loop heat exchanger and to the ground-loop system and is configured to receive the ground liquid from the ground-loop heat exchanger and the refrigerant from the hot-water-reservoir-loop exchanger and to transfer heat from the refrigerant to the ground liquid before returning the ground liquid to the ground-loop system for reheating. The thermostatic expansion valve is coupled between the subcooler heat exchanger and the ground-loop heat exchanger and is configured to control a flow of the refrigerant to the ground-loop heat exchanger.

In accordance with another aspect of the present disclosure, a suction line accumulator is coupled between the compressor and the ground-loop heat exchanger and is configured to control a flow of the refrigerant into the compressor from the ground-loop heat exchanger.

In accordance with a further aspect of the present disclosure, a circulation pump is coupled between the ground-loop heat exchanger and the ground loop system and is configured to circulate the liquid from the ground loop system through the ground-loop heat exchanger and through the subcooler heat exchanger prior to returning the liquid to the ground loop system. In other implementations, the circulation pump is coupled between the ground-loop heat exchanger and the subcooler heat exchanger and is configured to circulate the liquid from the ground-loop heat exchanger through the subcooler heat exchanger and through the ground loop system prior to the liquid returning to the ground-loop heat exchanger.

In accordance with yet another aspect of the present disclosure, a circulation pump is coupled between the subcooler heat exchanger and the ground loop system and is configured to circulate the liquid from the subcooler heat exchanger through the ground loop system and through the ground-loop heat exchanger prior to the liquid returning to the subcooler heat exchanger.

In accordance with a further aspect of the present disclosure, a circulation pump is coupled between the hot-water-reservoir-loop heat exchanger and the hot-water reservoir and is configured to circulate the water from the hot-water reservoir through the hot-water-reservoir-loop heat exchanger prior to returning the water to the hot-water reservoir.

In accordance with another aspect of the present disclosure, the ground loop system includes a plurality of pipes that are arranged in the Earth to enable the transfer of heat from the Earth to the liquid, such as water, in the pipes.

In accordance with yet another aspect of the present disclosure, the hot-water-reservoir-loop heat exchanger receives the refrigerant in a cooled, low-pressure gaseous state and outputs the refrigerant in a warmed, low-pressure gaseous state.

In accordance with a further aspect of the present disclosure, the subcooler heat exchanger receives the liquid from the ground-loop heat exchanger at a temperature that is colder than the water that is received from the ground loop system, and wherein the liquid output from the subcooler heat exchanger is warmer than the liquid received from the ground-loop heat exchanger.

In accordance with another aspect of the present disclosure, the subcooler heat exchanger outputs the refrigerant at a temperature that is colder than the temperature of the refrigerant received by the subcooler heat exchanger.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing and other features and advantages of the present disclosure will be more readily appreciated as the same become better understood from the following detailed description when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a system diagram of an implementation of a geothermal heating system in accordance with the present disclosure;

FIG. 2 is a system diagram of an implementation of a ground-loop system in accordance with the present disclosure;

FIGS. 3A and 3B are cross-sectional views of a geothermal heating system in accordance with the present disclosure; and

FIGS. 4A and 4B are cross-sectional views of another geothermal heating system in accordance with the present disclosure.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed implementations. However, one skilled in the relevant art will recognize that the implementations may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures or components or both associated with the environment of the present disclosure, including but not limited to the construction of the pumps, filters and other well-known aspects of the disclosure have not been shown or described in order to avoid unnecessarily obscuring descriptions of the various implementations.

Unless the context requires otherwise, throughout the specification and claims that follow, the word “comprise” and variations thereof, such as “comprises” and “comprising” are to be construed in an open inclusive sense, that is, as “including, but not limited to.” The foregoing applies equally to the words “including” and “having.”

Reference throughout this description to “one implementation” or “an implementation” means that a particular feature, structure, or characteristic described in connection with the implementation is included in at least one implementation. Thus, the appearance of the phrases “in one implementation” or “in an implementation” in various places throughout the specification are not necessarily all referring to the same implementation. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations.

FIG. 1 is a system diagram of an implementation of a geothermal heating system 100 formed in accordance with the present disclosure. The system 100 includes a ground-loop system 110, a hot-water reservoir 120, and a geothermal heat exchange system 102. The system 100 utilizes a ground-liquid loop 180 to circulate ground liquid between the ground-loop system 110 and the geothermal-heat-exchange system 102, a refrigerant loop 182 to transfer heat from the ground liquid to reservoir water, and a reservoir-water loop 184 to circulate the reservoir water between the hot-water reservoir 120 and the geothermal-heat-exchange system 102.

The hot-water reservoir 120 is a storage body that can hold a volume of water, referred to as reservoir water. Examples of the hot-water reservoir 120 include, but are not limited to, a hot-water tank, a hot tub or spa water storage chamber, a pool heating element, etc. The hot-water reservoir 120 can be used in commercial or residential settings. It should be recognized that the hot-water reservoir 120 can also be configured to store other types of liquid.

The ground-loop system 110 is an underground system that provides a liquid to the geothermal-heat-exchange system 102. The ground-loop system 110 allows for geothermal energy to be transferred from the ground to the liquid within the ground-loop system 110. This liquid may be referred to as the ground liquid, and may be water, a combination of water and anti-freeze, or other liquid that is suitable for pulling heat out of the ground and transferring that heat to a refrigerant in the geothermal-heat-exchange system 102. The ground-loop system 110 can be a closed-loop system that circulates and recycles the ground liquid between the ground-loop system and the geothermal-heat-exchange system 102 or an open-looped system that provides the ground liquid to the geothermal-heat-exchange system 102 but the ground liquid is discharged elsewhere and not directly recycled. One example of a ground-loop system 110 is illustrated in FIG. 2. In some implementations, the ground-loop system 110 may be above ground such that heat is transferred to the liquid in the ground-loop system from the ambient air or by solar energy.

Briefly, the geothermal-heat-exchange-system 102 includes a ground-liquid-loop heat exchanger 130, a suction line accumulator 132, a refrigerant compressor 134, a hot-water-reservoir-loop heat exchanger 136, a subcooler heat exchanger 138, and a thermostatic expansion valve 140.

Turning first to the ground-liquid loop 180, the ground-loop system 110 heats the ground liquid. The heated ground liquid is provided to the ground-loop system 110 via an output line 114. The geothermal-heat-exchange system 102 receives the heated ground liquid via an input line 152. The heated ground liquid is circulated to the ground-liquid-loop heat exchanger 130 via a line 154. The ground-liquid-loop heat exchanger 130 uses the heated ground liquid to heat a refrigerant. The ground liquid exits the ground-liquid-loop heat exchanger 130 via a line 156 at a temperature lower than it entered the ground-liquid-loop heat exchanger 130. The cooled ground liquid is provided to a subcooler heat exchanger 138 via the line 156. The subcooler heat exchanger 138 partially reheats the ground liquid, as further described below. The geothermal-heat-exchange system 102 provides the partially reheated ground liquid back to the ground-loop system 110 via an output line 158, and the ground-loop system 110 receives the partially reheated ground liquid via an input line 112.

The refrigerant loop 182 is configured to transfer heat from the ground liquid to reservoir water via a refrigerant. The ground-water-loop heat exchanger 130 receives the refrigerant via a line 170 and the heated ground liquid via the line 154. The refrigerant provided to the ground-water-loop heat exchanger 130 is mostly a cooled, low-pressure gas refrigerant. The ground-water-loop heat exchanger 130 is configured to enable the transfer of heat from the ground liquid to the refrigerant, resulting in a warmed, low-pressure gas refrigerant.

The warmed, low-pressure gas refrigerant is provided from the ground-water-loop heat exchanger 130 to the suction line accumulator 132 via a line 160. The suction line accumulator 132 temporarily stores the warmed, low-pressure gas refrigerant. The suction line accumulator 132 enables a constant volume of refrigerant to be provided to the compressor 134 via a line 162.

The compressor 134 pressurizes the warmed, low-pressure refrigerant by compressing it. This increase in pressure also increases the temperature of the refrigerant, resulting in a hot, high-pressure gas refrigerant. The hot, high-pressure gas refrigerant is provided from the compressor 134 to the hot-water-reservoir-loop heat exchanger 136 via a line 164.

The hot-water-reservoir-loop heat exchanger 136 also receives reservoir water via a line 176. The hot-water-reservoir-loop heat exchanger 136 transfers heat from the hot, high-pressure gas refrigerant to the reservoir water.

Briefly referring to the reservoir-water loop 184, the hot-water reservoir 120 stores the reservoir water. The reservoir water to be heated is provided to the geothermal-heat-exchange system 102 via an output line 124. The geothermal-heat-exchange system 102 receives the reservoir water via an input line 176. Reservoir water is provided to the hot-water-reservoir-loop heat exchanger 136 via the input line 176. The hot-water-reservoir-loop heat exchanger 136 heats the reservoir water by transferring heat from the hot, high-pressure gas refrigerant provided via the line 164. The heated reservoir water exits the hot-water-reservoir-loop heat exchanger 136 via a line 172 at a temperature higher than it entered the hot-water-reservoir-loop heat exchanger 136. The heated reservoir water is circulated and provided to the hot-water reservoir 120 via an output line 174, and the hot-water reservoir 120 receives the heated reservoir water via an input 122.

Returning to the refrigerant loop 182, the transfer of heat from the hot, high-pressure gas refrigerant to the reservoir water partially cools the refrigerant. This cooling can result in some of refrigerant being converted into a high-pressure liquid, while some of the refrigerant remaining as a high-pressure gas.

The partially cooled refrigerant is provided from the hot-water-reservoir-loop heat exchanger 136 to the subcooler heat exchanger 138 via a line 166. As described above, the cooled ground liquid from ground-water-loop heat exchanger 136 is also provided to the subcooler heat exchanger 138 via the line 156. The subcooler heat exchanger 138 transfers heat from the partially cooled refrigerant back to the ground liquid, resulting in a further decrease in the temperature of the refrigerant and an increase in the temperature of the ground liquid. The decreased temperature of the refrigerant enables a more complete phase transition of the refrigerant from a high-pressure gas to a high-pressure liquid.

From the subcooler heat exchanger 138, the high-pressure liquid refrigerant is provided to the thermostatic expansion valve 140 via a line 168. The thermostatic expansion valve 140 controls a flow of refrigerant provided to the ground-liquid-loop heat exchanger 130 via the line 170. In controlling the flow of the refrigerant, the pressure of the liquid refrigerant is reduced, which results in at least some of the refrigerant being converted into a low pressure gas and some into a low pressure liquid. The low pressure liquid continues to convert to a gas while it is transferred from the thermostatic expansion valve 140 to the ground-liquid-loop heat exchanger 130, where it is again heated by the transfer of heat from the ground liquid.

The additional transfer of heat from the refrigerant to the ground water by the subcooler heat exchanger provides multiple benefits to the system, some of which are mentioned here, but other benefits may also be obtained. One benefit of the subcooler heat exchanger is that the additional heat transfer from the refrigerant to the ground liquid helps to further pull the temperature of the refrigerant down so that a substantial amount of the refrigerant completes a phase change from a gas to a liquid. If the temperature of the refrigerant is not sufficiently reduced and converted to a liquid, the efficiency of the system may be diminished due to the properties and capabilities of the thermostatic expansion valve and the ground-liquid-loop heat exchanger.

Because the subcooler heat exchanger helps to reduce the temperature of the refrigerant, the temperature of the refrigerant entering the hot-water-reservoir-loop heat exchanger can be higher than without the subcooler heat exchanger. The higher temperature of the refrigerant at the hot-water-reservoir-loop heat exchanger results in a higher reservoir-water temperature. Without the subcooler heat exchanger, the temperature of the refrigerant at the hot-water-reservoir-loop heat exchanger should be lower to facilitate a proper phase transition from a gas to a liquid, which can result in cooler reservoir water.

Another benefit of the subcooler heat exchanger is that it increases the temperature of the ground liquid before the ground liquid is returned to the ground-loop system. As a result, the ground liquid in the ground-loop system is kept at a higher average temperature, which can reduce the amount of heat pulled from the ground when heating the ground liquid. By reducing the amount of heat pulled from the ground, the ground can maintain a temperature suitable for heating the ground liquid for a longer period of time.

As illustrated in FIG. 1, the geothermal-heat-exchange system 102 includes two circulation pumps 142 and 144. One circulation pump 142 circulates the reservoir water in the reservoir-water loop 184 between the geothermal-heat-exchange system 102 and the hot-water reservoir 120, and the other circulation pump 144 circulates the ground liquid in the ground-liquid loop 180 between the geothermal-heat-exchange system 102 and the ground-loop system 110.

Although FIG. 1 illustrates the circulation pump 142 as being connected to the output line 174, in other implementations, the circulation pump 142 may be connect to the input line 176. In yet other implementations, the geothermal-heat-exchange system 102 may not include this circulation pump 142. Rather, the hot-water reservoir 120 may include one or more circulation pumps for circulating the reservoir water to and from the geothermal-heat-exchange system 102.

Similarly, although FIG. 1 illustrates the circulation pump 144 as being connected to the input line 152, in other implementations, the circulation pump 144 may be connected to the output line 158 after the subcooler heat exchanger 138 or between the ground-water-loop heater exchanger 130 and the subcooler heat exchanger 138 on line 156. In yet other implementations, the geothermal-heat-exchange system 102 may not include this circulation pump 144. Rather, the ground-loop system 110 may include one or more circulation pumps for circulating the ground liquid through the ground-loop system and to and from the geothermal-heat-exchange system 102.

In various implementations, the geothermal-heat-exchange system 102 can be configured to be integrated into the hot-water reservoir 120 and connected to the ground-loop system 110, integrated into the ground-loop system 110 and connected to the hot-water reservoir 120, or a standalone unit that connects to the hot-water reservoir 120 and to the ground-loop system 110. In the latter configuration, the geothermal heat exchange system 102 can be sold separate from the hot-water reservoir 120 and the ground-loop system 110. In this way, the geothermal-heat-exchange system 102 can be used with a previously installed hot-water reservoir 120 and use a variety of different ground-loop systems that are already installed or are otherwise available on the market.

FIG. 2 is a system diagram of an implementation of a ground-loop system 200 formed in accordance with the present disclosure. The system 200 may be an implementation of the ground-loop system 110 in FIG. 1. In this illustration, the ground-loop system 200 is a closed-loop system.

Ground liquid is received by the system 200 via an input 212. The ground liquid is pumped through a series of pipes or tubes that are placed underground. Heat from the ground is absorbed by the ground liquid as the ground liquid flows through the pipes. In various applications, the more pipe surface area exposed to the ground can increase the amount of heat transferred to the ground liquid. In some implementations, the ground-loop system 200 may include a coil 216 or other pipes to increase the surface area of the pipes in contact with the ground. The heated ground liquid is provided to a geothermal-heat-exchange system, such as geothermal-heat-exchange system 102 of FIG. 1, via an output 214. After the geothermal-heat-exchange system transfers the heat from the ground liquid to water in a hot-water reservoir, the ground liquid is returned to the ground-loop system 200 via the input 212.

FIGS. 3A and 3B are cross-sectional views of a geothermal-heat-exchange system 300 formed in accordance with the present disclosure. The geothermal-heat-exchange system 300 may be one implementation of the geothermal-heat-exchange system 102 of FIG. 1. As described above, a ground-liquid loop circulates ground liquid between a ground-loop system and a geothermal-heat-exchange system, a refrigerant loop transfers heat from the ground liquid to reservoir water, and a reservoir-water loop circulates the reservoir water between a hot-water reservoir and the geothermal-heat-exchange system. FIGS. 3A and 3B illustrate the geothermal-heat-exchange system 300, but do not illustrate the ground-loop system and the hot-water reservoir for ease of illustration.

Ground liquid is provided to the geothermal-heat-exchange system 300 from the ground-loop system via an input 350. The input 350 is in fluid communication with a ground-loop heat exchanger 310. A circulation pump 304 is connected between the input 350 and the ground-loop heat exchanger 310, and is configured to circulate the ground liquid between the ground-loop system and the geothermal-heat-exchange system 300.

The ground-loop heat exchanger 310 is configured to enable the transfer of heat from the ground liquid to a refrigerant, which cools the ground liquid. In some implementations, the ground-loop heat exchanger 310 may be a three-way heat exchanger. A line 302 is connected between the ground-loop heat exchanger 310 and a subcooler heat exchanger 330 to provide the cooled ground liquid to the subcooler heat exchanger 330. The subcooler heat exchanger 330 is configured to partially reheat the ground liquid. The subcooler heat exchanger 330 is in fluid communication with an output 352 to return the partially reheated ground liquid back to the ground-loop system for reheating by geothermal energy.

Reservoir water is provided to the geothermal-heat-exchange system 300 from the hot-water reservoir via an input 354. The input 354 is in fluid communication with a hot-water-reservoir-loop heat exchanger 324. The hot-water-reservoir-loop heat exchanger 324 is configured to enable the transfer of heat from the refrigerant to the reservoir water. In some implementations, the hot-water-reservoir-loop heat exchanger 324 may be a double wall heat exchanger. The hot-water-reservoir-loop heat exchanger 324 is in fluid communication with an output 356 to provide the heated reservoir water to the hot-water reservoir. A circulation pump 320 is connected between the output of the hot-water-reservoir-loop heat exchanger 324 and the output 356, and is configured to circulate the reservoir water between the hot-water reservoir and the geothermal-heat-exchange system 300.

The refrigerant is in a closed refrigerant loop separate from the ground-liquid loop and the reservoir-water loop. A line 312 is in fluid communication with the ground-loop heat exchanger 310 to provide a refrigerant to the ground-loop heat exchanger 310. The ground-loop heat exchanger 310 is configured to enable the transfer of heat from the ground liquid to the refrigerant. A line 322 is connected between the ground-loop heat exchanger 310 to a suction line accumulator 316 to provide the heated refrigerant to the suction line accumulator 316. The suction line accumulator 316 provides a constant volume of refrigerant to a compressor 328 via a line 314 that is connected between the suction line accumulator 316 and a compressor 328. The compressor 328 is configured to increase the pressure, and thus the temperature, of the refrigerant. A line 318 is connected between the compressor and the hot-water-reservoir-loop heat exchanger 324 to provide the heated, pressurized refrigerant to the hot-water-reservoir-loop heat exchanger 324. The hot-water-reservoir-loop heat exchanger 324 is configured to enable the transfer of heat from the refrigerant to the reservoir water, which cools the refrigerant. The cooled refrigerant is provided to the subcooler heat exchanger 330 via a line 326. The subcooler heat exchanger 330 is configured to enable the transfer of heat from the refrigerant to the ground liquid, which partially reheats the ground liquid and further cools the refrigerant. A line 306 is connected between the subcooler heat exchanger 330 and a thermostatic expansion valve 308. The thermostatic expansion valve 308 is configured to regulate the flow of refrigerant to the ground-loop heat exchanger 310, which results in the refrigerant being cooled. The line 312 is connected between the thermostatic expansion valve 308 and the ground-loop heat exchanger 310 to provide the cooled refrigerant back to the ground-loop heat exchanger 310 for reheating.

FIGS. 4A and 4B are cross-sectional views of another implementation of a geothermal-heat-exchange system 400 formed in accordance with the present disclosure. The geothermal-heat-exchange system 400 may be one implementation of the geothermal-heat-exchange system 102 of FIG. 1. As described above, a ground-liquid loop circulates ground liquid between a ground-loop system and a geothermal-heat-exchange system, a refrigerant loop transfers heat from the ground liquid to reservoir water, and a reservoir-water loop circulates the reservoir water between a hot-water reservoir and the geothermal-heat-exchange system. FIGS. 4A and 4B illustrates the geothermal-heat-exchange system 400, but do not illustrate the ground-loop system and the hot-water reservoir for ease of illustration.

Similar to what is described above in conjunction with FIGS. 3A and 3B, ground liquid is provided to the geothermal-heat-exchange system 400 from the ground-loop system via an input 450. The input 450 is in fluid communication with a ground-loop heat exchanger 410. A circulation pump 404 is connected between the input 450 and the ground-loop heat exchanger 410, and is configured to circulate the ground liquid between the ground-loop system and the geothermal-heat-exchange system 400.

The ground-loop heat exchanger 410 is configured to enable the transfer of heat from the ground liquid to a refrigerant, which cools the ground liquid. A line 402 is connected between the ground-loop heat exchanger 410 and a subcooler heat exchanger 430 to provide the cooled ground liquid to the subcooler heat exchanger 430. The subcooler heat exchanger 430 is configured to partially reheat the ground liquid. The subcooler heat exchanger 430 is in fluid communication with an output 452 to return the partially reheated ground liquid back to the ground-loop system for reheating by geothermal energy.

Reservoir water is provided to the geothermal-heat-exchange system 400 from the hot-water reservoir via an input 454. The input 454 is in fluid communication with a hot-water-reservoir-loop heat exchanger 424. The hot-water-reservoir-loop heat exchanger 424 is configured to enable the transfer of heat from the refrigerant to the reservoir water. In some implementations, the hot-water-reservoir-loop heat exchanger 424 may be a three-way heat exchanger. The hot-water-reservoir-loop heat exchanger 424 is in fluid communication with an output 456 to provide the heated reservoir water to the hot-water reservoir. A circulation pump 420 is connected between the output of the hot-water-reservoir-loop heat exchanger 424 and the output 456, and is configured to circulate the reservoir water between the hot-water reservoir and the geothermal-heat-exchange system 400.

The refrigerant is in a closed refrigerant loop separate from the ground-liquid loop and the reservoir-water loop. A line 412 is in fluid communication with the ground-loop heat exchanger 410 to provide a refrigerant to the ground-loop heat exchanger 410. The ground-loop heat exchanger 410 is configured to enable the transfer of heat from the ground liquid to the refrigerant. In some implementations, the ground-loop heat exchanger 410 may be a three-way heat exchanger. A line 422 is connected between the ground-loop heat exchanger 410 to a suction line accumulator 416 to provide the heated refrigerant to the suction line accumulator 416. The suction line accumulator 416 provides a constant volume of refrigerant to a compressor 428 via a line 414 that is connected between the suction line accumulator 416 and a compressor 428. The compressor 428 is configured to increase the pressure, and thus the temperature, of the refrigerant. A line 418 is connected between the compressor and the hot-water-reservoir-loop heat exchanger 424 to provide the heated, pressurized refrigerant to the hot-water-reservoir-loop heat exchanger 424. The hot-water-reservoir-loop heat exchanger 424 is configured to enable the transfer of heat from the refrigerant to the reservoir water, which cools the refrigerant. The cooled refrigerant is provided to the subcooler heat exchanger 430 via a line 426. The subcooler heat exchanger 430 is configured to enable the transfer of heat from the refrigerant to the ground liquid, which partially reheats the ground liquid and further cools the refrigerant. A line 406 is connected between the subcooler heat exchanger 430 and a thermostatic expansion valve 408. The thermostatic expansion valve 408 is configured to regulate the flow of refrigerant to the ground-loop heat exchanger 410, which results in the refrigerant being cooled. The line 412 is connected between the thermostatic expansion valve 408 and the ground-loop heat exchanger 410 to provide the cooled refrigerant back to the ground-loop heat exchanger 410 for reheating.

It should be recognized that the various lines, parts, and various components described herein may be any of a variety of types known to those skilled in the art to be suitable for use in a heat pump. Similarly, the volume and capacity of the various components may be selected based on the application of the geothermal-heat-exchange system. For example, a geothermal-heat-exchange system implemented in accordance with the description herein to heat a 50 gallon hot-water tank may utilize smaller capacity components compared to a geothermal-heat-exchange system implemented in accordance with the description herein to heat a 500 gallon hot tub.

The various implementations described above can be combined to provide further implementations. Aspects of the implementations can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further implementations.

These and other changes can be made to the implementations in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific implementations disclosed in the specification and the claims, but should be construed to include all possible implementations along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure. 

1. A system for heating water that is used to heat water in a hot-water reservoir with heat obtained from liquid that is sourced by a ground-loop system, the system for heating water comprising: a ground-loop heat exchanger configured to receive a liquid from the ground-loop system that geothermally heats the liquid and to transfer heat from the liquid to a refrigerant; a compressor coupled to the ground-loop heat exchanger and configured to increase a pressure of the refrigerant received from the ground-loop heat exchanger; a hot-water-reservoir-loop heat exchanger coupled to the compressor and to the hot-water reservoir and configured to receive the refrigerant and transfer heat from the refrigerant to water received from the hot-water reservoir; a subcooler heat exchanger coupled to the hot-water-reservoir-loop heat exchanger and to the ground-loop system and configured to receive the liquid from the ground-loop heat exchanger and the refrigerant from the hot-water-reservoir-loop exchanger and to transfer heat from the refrigerant to the liquid before returning the liquid to the ground-loop system; and a thermostatic expansion valve coupled between the subcooler heat exchanger and the ground-loop heat exchanger and configured to control a flow of the refrigerant from the subcooler heat exchanger to the ground-loop heat exchanger.
 2. The system of claim 1, further comprising a suction line accumulator coupled between the compressor and the ground-loop heat exchanger and configured to control a flow of the refrigerant into the compressor from the ground-loop heat exchanger.
 3. The system of claim 1, further comprising a circulation pump coupled between the ground-loop heat exchanger and the ground loop system and configured to circulate the liquid from the ground loop system through the ground-loop heat exchanger and through the subcooler heat exchanger prior to returning the liquid to the ground loop system.
 4. The system of claim 1, further comprising a circulation pump coupled between the ground-loop heat exchanger and the subcooler heat exchanger and configured to circulate the liquid from the ground-loop heat exchanger through the subcooler heat exchanger and through the ground loop system prior to the liquid returning to the ground-loop heat exchanger.
 5. The system of claim 1, further comprising a circulation pump coupled between the subcooler heat exchanger and the ground loop system and configured to circulate the liquid from the subcooler heat exchanger through the ground loop system and through the ground-loop heat exchanger prior to the liquid returning to the subcooler heat exchanger.
 6. The system of claim 1, further comprising a circulation pump coupled between the hot-water-reservoir-loop heat exchanger and the hot-water reservoir and configured to circulate the water from the hot-water reservoir through the hot-water-reservoir-loop heat exchanger prior to returning the water to the hot-water reservoir.
 7. The system of claim 1, wherein the ground loop system includes a plurality of pipes that are arranged in the Earth to enable the transfer of heat from the Earth to the liquid.
 8. The system of claim 1, wherein the liquid is water.
 9. The system of claim 1, wherein the hot-water-reservoir-loop heat exchanger receives the refrigerant in a cooled, low-pressure gaseous state and outputs the refrigerant in a warmed, low-pressure gaseous state.
 10. The system of claim 1, wherein the subcooler heat exchanger receives the liquid from the ground-loop heat exchanger at a temperature that is colder than the water that is received from the ground loop system, and wherein the liquid output from the subcooler heat exchanger is warmer than the liquid received from the ground-loop heat exchanger.
 11. The system of claim 1, wherein the subcooler heat exchanger outputs the refrigerant at a temperature that is colder than the temperature of the refrigerant received by the subcooler heat exchanger.
 12. A system for heating water in a hot-water reservoir, comprising: a ground-loop heat exchanger configured to exchange heat from geothermally heated liquid sourced from a ground-loop system to a refrigerant; a compressor in fluid communication with the ground-loop heat exchanger, the compressor configured to increase a pressure of the refrigerant; a hot-water-reservoir-loop heat exchanger in fluid communication with the compressor, the hot-water-reservoir-loop heat exchanger configured to exchange heat from the refrigerant to the water received from the hot-water reservoir; a subcooler heat exchanger in fluid communication with the hot-water-reservoir-loop heat exchanger and the ground-loop system, the subcooler heat exchanger configured to exchange heat from the refrigerant to the liquid received from the ground-loop heat exchanger before returning the liquid to the ground-loop system; and a thermostatic expansion valve in fluid communication with the subcooler heat exchanger, the thermostatic expansion valve configured to control a flow of the refrigerant to the ground-loop heat exchanger.
 13. The system of claim 12, further comprising a suction line accumulator in fluid communication with the ground-loop heat exchanger and the compressor, the suction line accumulator configured to control a flow of the refrigerant into the compressor.
 14. The system of claim 12, further comprising a circulation pump in fluid communication with the ground loop system, the circulation pump configured to circulate the liquid through the ground loop system, the ground-loop heat exchanger, and the subcooler heat exchanger.
 15. The system of claim 12, further comprising a circulation pump in fluid communication with the hot-water reservoir, the circulation pump configured to circulate the water from the hot-water reservoir through the hot-water-reservoir-loop heat exchanger and back to the hot-water reservoir.
 16. The system of claim 12, wherein the ground loop system includes a plurality of pipes that are in fluid communication with the ground-loop heat exchanger and the subcooler heat exchanger, the plurality of pipes are configured to enable the transfer of heat from the Earth to the liquid.
 17. A method for heating a first liquid in a hot-liquid reservoir, comprising: receiving a second liquid from a ground-loop system that geothermally heats the second liquid; transferring heat from the second liquid to a third liquid by a ground-loop heat exchanger to increase a first temperature of the third liquid to a second temperature of the third liquid; compressing the third liquid by a compressor to increase a pressure and temperature of the third liquid from the second temperature to a third temperature of the third liquid; transferring heat from the third liquid to the first liquid by a hot-water-reservoir-loop heat exchanger to increase a temperature of the first liquid and reduce the third temperature of the third liquid to a fourth temperature of the third liquid; transferring heat from the third liquid to the second liquid by a subcooler heat exchanger prior to returning the second liquid to the ground-loop system to reduce the fourth temperature of the third liquid to a fifth temperature of the third liquid; and reducing the pressure of the third liquid by a thermostatix expansion valve to reduce the fifth temperature of the third liquid to the first temperature of the third liquid prior to the transferring of heat from the second liquid to the third liquid.
 18. The method of claim 17, wherein third liquid at the first temperature is in a cooled, low-pressure gaseous state and the third liquid at the second temperature is in a warmed, low-pressure gaseous state.
 19. The method of claim 17, wherein the third liquid at the fifth temperature is colder than third liquid at the fourth temperature. 